1. Field of the Invention
The present invention relates to computer-aided integrated circuit design tools. In particular, the invention relates to circuits and methods for use in a data path compiler, an integrated circuit design tool that translates a functional description of datapath elements into a hardware realization.
2. State of the Art
Datapath compilers are known in the art. These computer-aided integrated circuit design tools accept a functional user specification of desired datapath elements and from that specification generate a hardware circuit layout that realizes the desired function. The desired function may be a simple counting function. Often, however, the function is arithmetic. For example, the user may specify that a data word be added together with a predefined constant. The datapath element that performs this function may be referred to as a constant adder. Similarly, the user may specify that a data word be multiplied by a predefined constant. The datapath element that performs this function may be referred to as a constant multiplier. As used herein, the term "constant multiplier" refers to a special-purpose multiplier that multiplies a data word by a fixed, signed or unsigned constant. To accommodate variable word length and arbitrary constants, constant multipliers have typically required detailed design by a design engineer. That is, constant multipliers have not been readily compilable.